WO2013167051A2

WO2013167051A2 - Multi-domain route computation method and device, path computation element, and routing network

Info

Publication number: WO2013167051A2
Application number: PCT/CN2013/079628
Authority: WO
Inventors: 卢刚; 王大江
Original assignee: 中兴通讯股份有限公司
Priority date: 2012-11-30
Filing date: 2013-07-18
Publication date: 2013-11-14
Also published as: CN103023774B; EP2928125A2; US20150341255A1; CN103023774A; EP2928125A4; EP2928125B1; US9712426B2; WO2013167051A3

Abstract

Disclosed is a multi-domain route computation method, comprising: when it is determined that two or more domains deployed with a path computation element (PCE) exist in a network, computing a routing path between a first domain PCE and a tail domain PCE in the two or more domains deployed with a PCE by means of extended backward recursive path computation (BRPC), and computing a routing path in a domain except the two or more domains deployed with a PCE by using an RC. Also disclosed are a multi-domain route computation device, a PCE, and a routing network. The present invention can improve the path computation optimality to a great extent, and the path computation efficiency is pretty high.

Description

Multi-domain routing calculation method and device, path calculation unit and routing network

The present invention relates to a routing path computing technology, and in particular, to a multi-domain routing calculation method and device, a Path Computation Element (PCE), and a routing network. Background technique

In a multi-layer multi-domain network using Generalized Multiprotocol Label Switching (GMPLS), multiple nodes with different switching capabilities and rates can be divided into different domains or layers. These domains can be router domains and optical. An OTN (Optical Transport Network) domain or a Packet Transport Network (PTN) domain. In a multi-domain network divided by an autonomous system (AS), a Routing Controller (RC) or a Path Computation Element (PCE) can be used to calculate the end-to-end across multiple domains. path.

The Optical Internetworking Forum (OIF) is a standards organization that specializes in the interconnection of optical networks. In order to solve the interworking between multi-domain networks, the "E-NNI OSPFv2 -based Routing -2.0 Implementation Agreement" standard was established, and multi-domain interworking using RC and based on Domain to Domain Routing Protocol (DDRP) was proposed. Path calculation method. This method abstracts the intra-domain topology of each domain and represents it as an abstract link. It floods the inter-domain topology information of multiple domains through DDRP. The information includes inter-domain links, intra-domain abstract links, and each The boundary node information of each domain is shown in Figure 1. Based on the inter-domain topology, the inter-domain routing is calculated by the RC of the first domain, and then based on the calculated inter-domain paths (including inter-domain links, domain boundary nodes, intra-domain abstract links), and entries in each domain. The boundary node calculates a specific intra-domain route of each domain, and the signaling performs routing according to the calculated path, as shown in FIG. 2 . The Internet Engineering Task Force (IETF) proposed the use of PCE for multi-domain path calculation. Among them, RFC5441 proposes a PCE-based Backward-Recursive PCE-Based Computation (BRPC) algorithm. The algorithmic process relies on communication between mutually cooperating PCEs. The Path Computation Client (PCC) sends a Path Calculation Request PCReq message to the PCE in its domain. The PCReq message is forwarded between the PCEs of each domain until the request reaches the PCE of the domain in which the node responsible for calculating the Label Switching Path (LSP) is located. The PCE in the destination domain creates a virtual shortest path tree (VSPT) consisting of the potential path to the destination node, and sends the path tree to the previous PCE in the path computation response PCRep message. Then each PCE sequentially adds VSPT and sends it back to the PCE of the domain where the source node is located. This PCE uses VSPT to select an optimal end-to-end path and sends the path to the PCC, as shown in Figure 3. The method shown in Figure 3 requires that all domains participating in the BRPC algorithm support PCE, and each domain PCE supports the RFC5088 flooding automatic discovery function, so that each domain PCE is known to its neighbors. Of course, the IETF RFC 5152 also proposes a Per-domain Routing Computation method, the basic principle is similar to the OIF RC method.

At present, in practical applications, there are three scenarios: 1) If each domain in the domain sequence does not support PCE, the OIF RC calculation mode is adopted; 2) If each domain in the domain sequence supports PCE, the IETF PCE BRPC is adopted. Calculation method; 3) If there are domains in the domain sequence that support PCE, and some do not support, interworking calculation is required.

For the third scenario, the typical method currently used is as described in the Chinese Patent Application Publication No. CN101296178A, the disclosure of which is incorporated herein by reference. The segment calculation method determines whether the next domain has PCE by the boundary node of the pre-domain, and if it has PCE, it is calculated according to the first path calculation mode (BRPC algorithm of PCE) (as shown in the autonomous system 1 in FIG. 4); If you do not have a PCE, then Calculated according to the second path calculation method (per-domain path calculation algorithm) (as shown in the autonomous system 2 in Fig. 4). Finally, each domain sequentially calculates a route by using a first path calculation manner or a second path calculation manner, and finally completes signaling establishment according to the calculated route. Although this method partially solves the problem of interworking calculation, it still has the following defects: For the domain of BRPC calculation using PCE, it is still necessary to deploy PCE in consecutive domains, if there is any between two domains where PCE is deployed. If you deploy a PCE domain, you cannot use the BRPC algorithm. You can only use the path calculation method for each domain. This will greatly reduce the optimality of path calculation and result in inefficient path calculation. Summary of the invention

In view of this, the main object of the present invention is to provide a multi-domain routing calculation method and apparatus, a path calculation unit, and a routing network, which can quickly and efficiently calculate routing paths between different domains in multiple domains.

In order to achieve the above object, the technical solution of the present invention is achieved as follows:

A multi-domain routing calculation method includes:

When the number of domains in which the PCE is deployed in the network is two or more, the routing path is calculated by using the extended BRPC mode between the first domain PCE and the tail domain PCE in the domain where the two or more PCEs are deployed. Two or more domains outside the domain where PCE is deployed use RC to calculate routing paths.

Preferably, the routing path is calculated by using an extended BRPC mode between the first domain PCE and the tail domain PCE in the domain where the two or more PCEs are deployed, including:

After receiving the triggering request of the path calculation, the PCE determines whether the domain in which the PCE is located is a tail domain, and calculates the VSPT of the local domain when the tail domain is the tail domain, and further determines the domain and the downstream of the domain sequence in the domain of the PCE when the non-tail domain is a non-tail domain. If there is a domain in which the PCE is not deployed between the domains of the next deployed PCE, the VSPT of the domain is calculated when the domain is not present, and the domain is not in the domain where the PCE is deployed. The inter-domain link is used as an extended link topology and merged with the link topology of the domain in which the PCE is located to calculate the VSPT after the merged link topology.

Preferably, after the VSPT after the merged link topology is calculated, the method further includes: The corresponding VSPT routing path calculated by the extended link topology and the VSPT corresponding routing path calculated by the domain where the PCE is located are identified as different types of routing paths.

Preferably, the method further includes:

After the VSPT is calculated, when the domain where the PCE is located is the non-first domain in the domain where the two or more PCEs are deployed, the calculated VSPT is sent to the next deployed PCE in the upstream of the domain sequence. Domain PCE.

Preferably, the PCE receives the trigger request of the path calculation, including:

Receiving, by the PCE, a path calculation request message;

Alternatively, the PCE receives the VSPT.

Preferably, after the routing path is calculated by using the extended BRPC mode between the first domain PCE and the tail domain PCE in the domain where the PCE is deployed, the method further includes:

Sending signaling from the source node to the destination node;

When the signaling is routed to the VSPT corresponding routing path calculated by the domain in which the PCE is located, the signaling is routed according to the VSPT corresponding routing path;

When the signaling is routed to the VSPT corresponding routing path calculated by the extended link topology, the RC calculates the strict hopping path in the domain corresponding to the loose hopping path of the domain in which the PCE is not deployed, and calculates the strict hop path routing path. Signaling.

A multi-domain routing computing device includes a determining unit and a computing unit, wherein:

Determining a unit, configured to determine that the domain in which the PCE is deployed in the network is two or more, triggering the computing unit;

a computing unit configured to calculate a routing path by using an extended BRPC method between the first domain PCE and the tail domain PCE in the domain where the two or more PCEs are deployed, where the two or more domains are deployed with PCE The domain uses RC to calculate the routing path.

Preferably, the calculating unit comprises a receiving subunit, a first determining subunit, a second determining subunit, a first calculating subunit and a second calculating subunit, wherein: a receiving subunit configured to receive a trigger request for path calculation;

a first determining subunit, configured to determine whether a domain in which the PCE to which the computing unit belongs is a tail domain, triggering the first computing subunit when triggered; and triggering the second determining subunit when not a tail domain;

a second determining sub-unit, configured to determine whether there is a domain in which the PCE is not deployed between the domain where the PCE to which the computing unit belongs and the domain of the next deployed PCE in the downstream of the domain sequence, and the first computing sub-trigger is triggered when not present Unit; triggering the second computing subunit when present;

a first computing subunit configured to calculate a VSPT of a domain in which the computing unit belongs to the PCE;

a second computing sub-unit, configured to use an intra-domain abstract link between the domain in which the PCE is not deployed, and an inter-domain link between domains in which the PCE is not deployed as an extended link topology, and where the computing unit belongs to the PCE The link topology of the domain is merged, and the VSPT of the merged link topology is calculated.

Preferably, the calculating unit further includes an identifier subunit configured to: after the VSPT of the merged link topology is calculated by the second calculating subunit, the VSPT corresponding routing path calculated by the extended link topology, The VSPT corresponding routing path identifier calculated by the domain where the computing unit belongs to the PCE is a different type of routing path.

Preferably, the calculating unit further includes a third determining subunit and a sending subunit, where: the third determining subunit is configured to: after calculating the VSPT, determining that the domain where the PCE is located is the two or more deployments When there is a non-first domain in the domain of the PCE, the sending subunit is triggered; the sending subunit is configured to send the calculated VSPT to the PCE of the next domain in which the PCE is deployed upstream in the domain sequence.

Preferably, the receiving subunit is further configured to receive a path calculation request message; or, receive a VSPT.

Preferably, the device further includes a sending unit and a routing unit, where:

a sending unit, configured to send signaling from the source node to the destination node; a routing unit, configured to: when the signaling is routed to a VSPT corresponding routing path calculated by a domain where the PCE is located, routing the signaling according to the VSPT corresponding routing path; and routing the signaling to the extended link When the VSPT corresponding routing path is calculated, the RC calculates a strict hop path within the domain corresponding to the loose hop path of the domain in which the PCE is not deployed, and routes the signaling according to the calculated strict hop path.

A path calculation unit includes a receiving unit, a first determining unit, a second determining unit, a first calculating unit, and a second calculating unit, where:

a receiving unit configured to receive a trigger request for path calculation;

a first determining unit, configured to determine whether the domain in which the path calculation unit is located is a tail domain, triggering the first computing unit when the tail domain is the second determining unit; Configuring to determine whether there is a domain in which the PCE is not deployed between the domain in which the path calculation unit is located and the domain of the next deployed PCE in the domain sequence, and triggering the first computing unit when not present; Second computing unit;

a first calculating unit, configured to calculate a virtual shortest path tree VSPT of a domain in which the path calculating unit is located;

a second computing unit, configured to use an intra-domain abstract link of the domain in which the PCE is not deployed, and an inter-domain link between domains in which the PCE is not deployed as an extended link topology, and the domain in which the path calculation unit is located The link topology is merged to calculate the VSPT of the merged link topology.

Preferably, the path calculation unit further includes an identification unit configured to: after the second computing unit calculates the VSPT of the merged link topology, calculate a VSPT corresponding routing path through the extended link topology, by using the The VSPT corresponding routing path calculated by the domain where the path calculation unit is located is identified as a different type of routing path.

Preferably, the path calculation unit further includes a third determining unit and a sending unit, where: the third determining unit is configured to: after calculating the VSPT, determining that the domain in which the PCE is located is the PCE in which the two or more are deployed The sending unit is triggered when the non-first domain in the domain is in the domain; The sending unit is configured to send the calculated VSPT to the PCE of the next domain in which the PCE is deployed upstream in the domain sequence.

Preferably, the receiving unit is further configured to receive a path calculation request message; or, receive the VSPT.

A routing network includes more than one routing domain, and the routing domain is provided with the foregoing path computing unit.

In the present invention, when it is determined that the domain in which the PCE is deployed in the network is two or more, the reverse recursive path is used to calculate the BRPC mode between the first domain PCE and the tail domain PCE in the domain where the two or more PCEs are deployed. The routing path is calculated, and the routing path is calculated by using the inter-domain routing protocol DDRP in the domain other than the two or more domains in which the PCE is deployed. The calculation of the routing path by using the BRPC method is as follows: After receiving the trigger request of the path calculation, the PCE determines whether the domain where the PCE is located is a tail domain, and when the tail domain is a tail domain, the virtual shortest path tree VSPT of the domain is calculated, which is a non-tail domain. Determining whether there is a domain in which the PCE is not deployed between the domain where the PCE is located and the domain of the next deployed PCE in the downstream of the domain sequence. If not, the virtual shortest path tree VSPT of the local domain is calculated. The intra-domain link between the domain of the PCE domain and the inter-domain link between the domains where the PCE is not deployed is used as the extended link topology and merged with the link topology of the domain where the PCE is located to calculate the merged link topology. VSPT. The technical solution of the present invention is directed to the hybrid topology of the domain where the PCE is deployed and the domain where the PCE is not deployed. The domain topology of the domain where the PCE is not deployed is used as the extended topology of the inter-domain link in the calculation process of the original BRPC algorithm. And use the topology to generate the virtual shortest path tree of the domain in the calculation of the BRPC of each PCE, thereby solving the problem that the BRPC algorithm cannot be implemented due to the existence of the domain in which the PCE is not deployed, and improving the optimality of the path. DRAWINGS

Figure 1 is a schematic diagram of DDRP topology generation using RC;

Figure 2 is a schematic diagram of multi-domain path calculation using RC;

3 is a schematic diagram of multi-domain path calculation using PCE; 4 is a schematic diagram of multi-domain routing interworking calculation;

FIG. 5 is a schematic diagram of multi-domain routing calculation according to the present invention; FIG.

6 is a schematic diagram of multi-domain routing calculation according to Embodiment 1 of the present invention;

7 is a schematic diagram of multi-domain routing calculation according to Embodiment 2 of the present invention;

8 is a schematic diagram of multi-domain routing calculation according to Embodiment 3 of the present invention;

9 is a schematic structural diagram of a multi-domain routing computing device according to an embodiment of the present invention; FIG. 10 is a schematic structural diagram of a computing unit of a multi-domain routing computing device according to an embodiment of the present invention;

FIG. 11 is a schematic structural diagram of a path calculation unit according to an embodiment of the present invention. detailed description

The present invention will be further described in detail below with reference to the accompanying drawings.

The present invention is directed to a hybrid network of a domain in which a PCE is deployed in a network and a domain in which a PCE is not deployed. The existing BRPC algorithm is extended, and the domain topology of the domain in which the PCE is not deployed is used as the inter-domain link in the calculation process of the original BRPC algorithm. The extension topology is used, and the topology is used to generate the virtual shortest path tree of the domain in the BRPC calculation of each PCE. First, before the cross-domain path calculation is implemented, the RC DDRP is used for the domain where the PCE is not deployed, and the domain topology is flooded, including the information of the inter-domain link, the intra-domain abstract link, and the domain boundary node. For the domain where the PCE is deployed, you need to configure its PCE neighbor information or use the automatic discovery information of RFC5088 to flood the PCE to automatically obtain PCE neighbor information. Then, the cross-domain path calculation is started. If the domain of the PCE has not been configured, the path calculation method of each domain is always used until the signaling reaches the domain where the PCE is configured. The domain PCE is the first domain PCE of the BRPC algorithm. The domain sequence, in turn, sends a path computation request until the PCE of the domain of the last configured PCE in the domain sequence ends, and the domain PCE acts as the tail domain PCE of the BRPC algorithm. The BRPC algorithm is used between the first domain PCE and the tail domain PCE. For the domain topology of the domain where the PCE is not configured, it is used as the extended topology of the inter-domain link. Its nearest upstream domain PCE is used in BRPC calculations. When the entire BRPC process is complete, the path segment in the domain where the PCE is deployed is represented as a strict hop path, and the path segment in the domain where the PCE is not deployed is represented as a loose hop path. Finally, the route establishment signaling calculated along the BRPC can be directly established for the strict hop path. For the loose hop path, the path calculation in the specific domain is completed in each domain, and signaling is established. If there is a domain in which the PCE is not deployed after the last domain in which the PCE is deployed, the per-domain path calculation algorithm is used to calculate the route until the destination node is reached, and the multi-domain routing interworking calculation is completed.

The present invention extends the use scenario of the BRPC algorithm so that only a minimum of two domains in the domain sequence can be deployed to deploy the PCE to use the BRPC algorithm, and there is no limit to the relative positions of the domains of the two deployed PCEs in the domain sequence. Of course, the closer the two are to the ends, the more obvious the advantages of the method of the invention. Moreover, in the case that the domain in which the PCE is deployed and the domain in which the PCE is deployed are spaced apart from each other in the domain sequence, the technical solution of the present invention can also complete the calculation by using only one BRPC calculation process to ensure the path optimality to the greatest extent.

The technical solution of the present invention has no limitation on the designation or calculation of the domain sequence, and the domain in which the PCE is deployed and the domain in which the PCE is not deployed may be arbitrarily arranged in the domain sequence. Moreover, the inter-domain topology flooding of the domain where the PCE is not deployed and the neighbor discovery of the PCE are both prior art and need not be extended for the method of the present invention.

As shown in Figure 5 (a), it is assumed that multi-domain routing from SN (source node) to DN (destination node) needs to be calculated, where the domain that passes through exists has a domain in which PCE is deployed, and a domain in which PCE is not deployed. The calculation process will be described below using the method of the present invention.

In the present invention, the following convention is made:

1) AS ( 0 ), AS ( N ): respectively represent the domain of the source node and the domain of the destination node for multi-domain routing interworking calculation;

2) AS ( 1 ), AS ( n ): indicates the first domain in the multi-domain routing domain to deploy the PCE and the last domain in which the PCE is deployed; 3) AS (i): indicates a domain of a multi-domain routing domain sequence in which no PCE is deployed;

4) AS ( i-1 ): indicates the domain in which the PCE is deployed in the nearest upstream domain of the AS (i) domain;

5) AS ( i+1 ): indicates the domain in which the PCE is deployed in the nearest downstream domain of the AS (i) domain;

6) PCE ( 1 ), PCE ( n), PCE ( i-1 ), PCE ( i+1 ): represent AS ( 1 ), AS (n), AS (il), AS (i+1) Corresponding PCE unit;

7) SN, DN: respectively represent the source node in AS ( 0 ) and the destination node in AS ( N );

8) SN, DN': an ingress boundary node indicating the arrival of the signaling of AS (1) and an egress boundary node leaving the signaling of AS (n);

9) BN-en, BN-ex: respectively represent the inbound and outbound nodes in each domain;

10) Al, A2, A3, A4, Bl, B2, B3, B4, Cl, C2: represent the boundary nodes of AS ( i-1 ), AS (i), AS (i+1 ).

The above conventions are only used to facilitate the description of the method of the present invention, and do not limit the manner in which the network of the present invention is networked. Since the method of the invention does not involve the determination of domain sequences, all methods of the invention are based on a given domain sequence (domain-passing sequences, such as AS1_>AS2 ->AS3).

The process of multi-domain routing interworking calculation of the present invention is described as follows:

Step 1: Each domain uses DDRP to advertise its inter-domain topology information, including domain border nodes, inter-domain links, and intra-domain abstract links, as shown in Figure 1.

Step 2: The PCEs of each domain that has a PCE are automatically discovered by flooding the PCE to obtain the neighbor relationship of the PCE. PCE auto-discovery information is not flooded for domains that do not have a PCE deployed. Use SN or BN-en to find the PCE auto discovery information in this domain to determine whether PCE is deployed in the domain.

Step 3: As shown in Figure 5 (a), starting from AS (0), along the domain sequence, SN or BN-en determines whether the domain is a domain where PCE is deployed:

1) If the domain of the PCE is not deployed, and the AS (N) is not reached, the domain path calculation method is used to calculate the domain route (the local domain BN-en to the local domain BN-ex), and the domain BN-ex is selected. BN-en of the next domain. Route signaling to the BN-en. Repeat step 3;

2) If it is a domain where PCE is deployed, go to step 4;

3) If the domain of the PCE is not deployed, and the AS (N) has been reached, the domain path calculation method is used to calculate the domain route (the local domain BN-en to DN), and the signaling is routed to the DN, and step 8 is performed;

Step 4: PCE (1) uses AS ( 1 ) as the first domain of BRPC calculation, and according to the neighbor relationship of PCE, finds the domain AS (n) of the last deployed PCE in the domain sequence, and uses it as the tail domain of BRPC calculation. AS (1) uses the inbound boundary node of the current signaling to the local domain as the source node of the BRPC algorithm, and according to the DDRP inter-domain topology, selects the exit boundary node of AS (n) as the destination node of the BRPC algorithm. PCE (1) sends a BRPC path calculation request message along the PCE sequence until PCE (n), as shown in Figure 5 (a);

Step 5: During the processing of the BRPC, for i = n to 1, AS ( i ) is handled as follows:

1) If i = n, the PCE (n) of AS (n) calculates the local VSPT (n) tree according to the general BRPC tail domain calculation method, and sends the VSPT (n) tree to the route calculation response message. The upstream domain PCE, repeat step 5;

2) If l<i<n, for each AS (i), further, according to AS (i) whether to deploy PCE, according to Method A and Method B respectively:

Method A (Deployed PCE):

A-1: PCE of AS (i) (i) Calculate the local VSPT (i) tree according to the intermediate domain calculation method of the general BRPC, and insert the VSPT (i) tree into the route calculation response message, by PCE (i) ) sent to the upstream domain PCE processing, repeat step 5;

Method B (PCE not deployed):

B-1: As shown in FIG. 5(b), PCE (i+1) transmits VSPT (i+1) to PCE (i-1) through a path calculation response message. According to the BRPC algorithm, PCE (i-1) needs to calculate the VSPT tree from A1 and A2 to the destination node DN. The AS(i) domain topology is an inter-domain link (A3-B1, A4-B2). B3-C1, B4-C2), intra-domain abstract links (Bl-B3, Bl-B4, B2-B3, B2-B4);

B-2: As shown in Figure 5 (c), PCE (i-1) regards the domain topology of AS (i) as the local (AS (i-1)) outbound node (A3/A4) to the downstream The domain (AS ( i+1 )) enters the inter-domain link extension topology of the border node C1/C2, and the intra-domain actual topology (A1/A2 to A3/4) in AS (il) is merged as the local domain BRPC calculation. Topology used;

B-3: As shown in Figure 5 (c), PCE (i-1) calculates the shortest path from A1/A2 to C1/C2 and splices it with the downstream domain VSPT (i+1) tree to calculate the local VSPT (i -1) Tree, where, in particular, the path of VSPT (i-1) in AS ( i ) is represented by a loose hop path, while in AS ( i-1 ) the path is represented by a strict hop path. The PCE (i-1) carries the VSPT (i-1) tree in the route calculation response message, and sends it to the upstream domain PCE for processing by the PCE (i-1), and repeats step 5;

3) If i = 1, AS ( 1 ) PCE ( 1 ) according to the general BRPC first domain calculation method, calculate the domain VSPT ( 1 ) tree, and generate the final path to SN, to DN, go to step 6;

Step 6: Signaling starts from the SN, and routes along the calculated SN, to DN, path. Further, in the route, the route represented by the strict hop path is directly routed; for the path represented by the loose hop path, the intra-domain calculation process between the two loose hop paths is initiated in the domain, and the calculation mode and the general order are The calculation process in the domain is consistent, and step 7 is performed;

Step 7: The signaling arrives at the DN', and the subsequent domains are all domains in which the PCE is not deployed. The general path calculation method is used to calculate the route, and the signaling is routed until the signaling reaches the DN, and step 8 is performed;

Step 8: The multi-domain routing interworking calculation is completed.

Embodiment 1

The application scenario of this example is as follows: The first domain and the tail domain are the domains where the PCE is deployed, and the intermediate domain is the domain where the PCE is not deployed.

As shown in Figure 6, four ASs (AS (1), AS (2), AS (3), AS (4)) are shown, where AS (1) and AS (4) deploy PCE (respectively PCE (1) and PCE (4)), while AS (2) and AS (3) did not deploy PCE. Rl and R15 are source nodes and destinations for multi-domain path computation Node. The link cost in the topology is 1. The inter-domain topology of each domain has been flooded by DDRP, and the automatic discovery information of PCE is also flooded according to the requirements of RFC5088. PCE (1) and PCE (4) can see the inter-domain topology and establish the neighbor relationship of PCE. The multi-domain routing calculation process is as follows:

(1) The path calculation request message is sent from R1 to PCE (1), requiring PCE (1) calculation

Multi-domain path from R1 to R15;

(2) PCE (1) determines the last PCE in the domain sequence as PCE (4) according to the domain sequence and the neighbor relationship of PCE in the automatic discovery information of PCE, and the corresponding domain is AS (4), and forwards to PCE (4). Path calculation request message;

(3) PCE (4) calculates the VSPT tree of this domain, denoted as VSPT (4), and carries VSPT(4) in the path calculation response message and returns it to PCE (1);

(4) After receiving the VSPT ( 4 ) of PCE ( 4 ), PCE ( 1 ) will inter-domain link and intra-domain abstract link in AS ( 2 ) and AS ( 3 ) in the inter-domain topology (shown by dashed line) As an inter-domain link extension topology between PCE (1) and PCE (4), then PCE (1) merges its local domain topology and inter-domain link extension topology to calculate R1 to The optimal path of R13 and R1 to R14, and spliced with the path in VSPT (4) to form VSPT (1), that is, the end-to-end path, expressed as ERO (display routing object): R 1 -R2-R4- R7-R9-R 11 -R 13 -R 15;

(5) The signaling is routed along the ERO to R4, ERO= R4-R7-R9-R11-R13-R15;

(6) R4-R7 is a loose hop path. The R4 to R7 domain path is calculated at R4, which is R4-R6-R7, and the extended ERO is R4-R6-R7-R9-R11-R13-R15, which is routed along the ERO to R9. , ER0=R9-R11-R13-R15;

(7) R9-R11 is a loose hop path. The intra-domain path of R9-R11 is calculated by R9, which is R9-R11, and the extended ERO is R9-R11-R13-R15, which is routed along the ERO to Rl l, ER0=R11-R13- R15;

(8) R11-R13-R15 are strict hop paths, routing signaling in sequence, signaling reaches R15, and the multi-domain path calculation process from R1 to R15 ends. Embodiment 2

The application scenario of this example is as follows: The intermediate domain is the domain where PCE is deployed, and the first domain and the tail domain are domains where PCE is not deployed.

As shown in Figure 7, four ASs (AS (1), AS (2), AS (3), AS (4)) are shown, where AS (2) and AS (3) deploy PCE (respectively PCE (2) and PCE (3)), while AS (1) and AS (4) do not deploy PCE. Rl and R15 are the source and destination nodes for multi-domain path computation. The link cost in the topology is 1. The inter-domain topology of each domain has been flooded by DDRP, and the automatic discovery information of PCE is also flooded according to the requirements of RFC5088. PCE (2) and PCE (3) can see the inter-domain topology and establish the neighbor relationship of PCE. The multi-domain routing calculation process is as follows:

(1) R1 finds that PCE is not deployed in this domain. The path calculation method is used for each domain. The path from R1 to R2 is calculated as R1-R2, and the signaling is routed to R2. The entry boundary node of the next domain is selected by R2. R4, the signaling arrives at the inbound boundary node R4 of the AS (2) along the route;

(2) R4 of AS (2) finds that the PCE is deployed in this domain, and then initiates a BRPC path calculation request message to PCE (2);

(3) PCE (2) determines the last PCE in the domain sequence as PCE (3) according to the domain sequence and the neighbor relationship of PCE in the automatic discovery information of PCE, and the corresponding domain is AS (3). PCE (2) uses R4 as the source node for BRPC calculation, and selects the exit boundary node R11 of PCE (3) as the destination node for BRPC calculation, and forwards the path calculation request message to PCE (3);

(4) PCE (3) calculates the VSPT tree of this domain, denoted as VSPT (3), and returns VSPT(3) to the path computation response message and returns it to PCE (2);

(5) PCE (2) returns the path calculation response message to the R3 node, and the path ERO is: R4-R6-R7--R9-R11, and the ERO is a strict hop path;

(6) The signaling is routed to Rll along the strict hop path in the ERO, and the ingress node of the next domain is selected by R11 as R13; (7) If R3 of AS (4) finds that PCE is not deployed in this domain, the path calculation method of each domain is used to calculate the local route, select the path of R13-R15, and route the signaling to R15. Then the multi-domain path calculation process End.

Embodiment 3

The application scenario of this example is as follows: Deploy the domain of the PCE and the domain spacing of the Deployed PCE. As shown in Figure 8, five ASs (AS (1), AS (2), AS (3), AS (4), AS (5)) are shown, where AS (1), AS (3), AS (5) deployed PCE (PCE (1), PCE (3), PCE (5)), while AS (2) and AS (4) did not deploy PCE. Rl and R19 are source and destination nodes for multi-domain path computation. The link cost in the topology is 1. The inter-domain topology of each domain has been flooded by DDRP, and the automatic discovery information of PCE has also been flooded according to the requirements of RFC5088. PCE (1), PCE (3), and PCE (5) can see the inter-domain topology and establish a PCE neighbor relationship. The multi-domain routing calculation process is as follows:

(1) R1 finds that the domain deploys PCE and requests multi-domain path calculation from the domain PCE (1).

(2) PCE (1) determines that the last PCE in the domain sequence is PCE (5) according to the domain sequence and the neighbor relationship of PCE in the automatic discovery information of PCE, and the domain is AS (5). PCE (1) uses R1 as the source node for BRPC calculation, and R19 is the destination node for BRPC calculation, and forwards the path calculation request message to the downstream domain PCE;

(3) PCE (3) receives the path calculation request message and continues to forward to the PCE (5);

(4) PCE (5) judges that R19 is the domain node, calculates the local VSPT (5) tree (ERO 1: R17-R19, ER02: R18-R19), and returns it to PCE through the path calculation response message (3) ;

(5) After receiving the VSPT (5) of the PCE (5), the PCE (3) uses the inter-domain link of the AS ( 4 ) in the inter-domain topology and the intra-domain abstract link (shown by the dotted line) as the PCE ( 3 ) Inter-domain link extension topology with PCE (5), then PCE (3) merges its local domain topology and inter-domain link extension topology to calculate R9/R10 to R17/R18 The optimal path is spliced with the path in VSPT ( 5 ) to form VSPT ( 3 ), denoted as ERO (display route object): R9-R11-R13-R15-R17-R19 and R10-R11-R13-R15-R17-R19, and return to PCE (1) by path calculation response message;

(6) After receiving the VSPT ( 3 ) of PCE ( 3 ), PCE ( 1 ) takes the inter-domain link of AS ( 2 ) in the inter-domain topology and the intra-domain abstract link (shown by dashed line) as PCE ( 1 ) Inter-domain link extension topology with PCE (3), then PCE (1) merges its local domain topology and inter-domain link extension topology to calculate the optimal R1 to R9/R10 The path is spliced with the path in VSPT ( 3 ) to form VSPT ( 1 ), which is the end-to-end path, denoted as ERO (display routing object): R1-R2-R4-R7-R9-R11-R13-R15 -R17-R19, and return to R1 through the path calculation response message;

(7) After receiving the path calculation response message, R1 routes to R4 along the ERO path, and ERO is: R4-R7-R9-R11-R13-R15-R17-R19;

(8) R4 finds that R4-R7 is a loose hopping path, initiates the intra-domain calculation process of the domain, obtains the R4-R6-R7 path, and routes the signaling to R7. The ERO is: R7-R9-R11-R13-R15- R17-R19;

(9) The R7 signaling continues to be routed to R13 along the strict hop path. The ERO is: R13-R15-R17-R19;

(10) R13 finds that R13-R15 is a loose hopping path, initiates the intra-domain calculation process of the local domain, obtains the R13-R15 path, and routes the signaling to R17. The ERO is: R17-R19;

(11) R17 continues the path signaling to R19 according to the strict hop path, and the multi-domain path calculation process ends.

Since there are many combinations of the domain in which the PCE is deployed and the domain in which the PCE is not deployed in the multi-domain routing interworking calculation, the technical solution of the present invention is not limited to the above embodiment.

FIG. 9 is a schematic structural diagram of a multi-domain routing computing device according to an embodiment of the present invention. As shown in FIG. 9, the multi-domain routing computing device of the embodiment of the present invention includes a determining unit 90 and a computing unit 91, where:

The determining unit 90 is configured to determine that when the domain in which the PCE is deployed in the network is two or more, Sending the calculation unit 90;

The calculating unit 91 is configured to calculate a routing path by using a BRPC method between the first domain PCE and the tail domain PCE in the domain where the two or more PCEs are deployed, where the two or more domains with the PCE are deployed. The domain uses the inter-domain routing protocol DDRP to calculate the routing path.

10 is a schematic structural diagram of a computing unit 91 of a multi-domain routing computing device according to an embodiment of the present invention. As shown in FIG. 10, the computing unit 91 of the embodiment of the present invention includes a receiving subunit 910, a first determining subunit 911, and a first The second determining subunit 912, the first calculating subunit 913 and the second calculating subunit 914, wherein:

The receiving subunit 910 is configured to receive a trigger request for path calculation;

The first determining subunit 911 is configured to determine whether the domain in which the PCE to which the computing unit 91 belongs is a tail domain, when the first computing subunit 913 is triggered, and the second determining subunit is triggered when it is a non-tailing domain. 912;

The second determining sub-unit 912 is configured to determine whether there is a domain in which the PCE is not deployed between the domain where the PCE to which the computing unit 91 belongs and the domain of the next deployed PCE in the downstream of the domain sequence. a calculating subunit 913; triggering the second calculating subunit when present;

a first computing sub-unit 913, configured to calculate a virtual shortest path tree VSPT of a domain in which the PCE to which the computing unit 91 belongs;

The second computing sub-unit 914 is configured to use an intra-domain abstract link of the domain in which the PCE is not deployed, and an inter-domain link between domains in which the PCE is not deployed as an extended link topology, and belong to the computing unit 91. The link topology of the domain where the PCE is located is merged, and the VSPT of the merged link topology is calculated.

On the basis of the calculation unit 91 shown in FIG. 10, the calculation unit 91 of the present embodiment further includes an identification subunit (not shown in FIG. 10) configured to calculate the merged link extension in the second calculation subunit 914. After the VSPT, the VSPT corresponding routing path calculated by the extended link topology and the VSPT corresponding routing path calculated by the domain in which the computing unit 91 belongs are identified as different types of routing paths. On the basis of the calculation unit 91 shown in FIG. 10, the calculation unit 91 further includes a third determination subunit (not shown in FIG. 10) and a transmission subunit (not shown in FIG. 10), wherein:

a third determining subunit, configured to: after the VSPT is calculated, determine that the domain where the PCE is located is a non-first domain in the domain in which the two or more PCEs are deployed, triggering the sending subunit; And configured to send the calculated VSPT to the PCE of the next deployed PCE domain upstream of the domain sequence.

The receiving subunit 910 is further configured to receive a path calculation request message; or, receive the VSPT.

Based on the multi-domain routing computing device shown in FIG. 9, the multi-domain routing computing device of this embodiment further includes a transmitting unit (not shown in FIG. 9) and a routing unit (not shown in FIG. 9), where: a sending unit, configured to send signaling from the source node to the destination node;

a routing unit, configured to: when the signaling is routed to a VSPT corresponding routing path, routing the signaling according to the VSPT corresponding routing path; and routing the signaling to a VSPT corresponding routing path calculated by using the extended link topology The intra-domain strict hop path corresponding to the loose hop path of the domain in which the PCE is not deployed is further calculated, and the signaling is routed according to the calculated strict hop path.

Those skilled in the art should understand that the implementation functions of the various units and processing subunits in the multi-domain routing computing device shown in FIG. 9 can be understood by referring to the related description of the foregoing multi-domain routing calculation method. It should be understood by those skilled in the art that the functions of the various units and processing subunits in the multi-domain routing computing device shown in FIG. 9 can be implemented by a program running on a processor, or can be implemented by a specific logic circuit.

FIG. 11 is a schematic structural diagram of a path calculation unit according to an embodiment of the present invention. As shown in FIG. 11, a path calculation unit according to an embodiment of the present invention includes a receiving unit 1110, a first determining unit 1111, a second determining unit 1112, and a first calculation. Unit 1113 and second computing unit 1114, wherein:

The receiving unit 1110 is configured to receive a trigger request for path calculation;

The first determining unit 1111 is configured to determine whether the domain where the path calculation unit is located is a tail domain, The first computing unit 1113 is triggered when the first computing unit 1113 is triggered; the second determining unit 1112 is triggered when it is a non-tailing domain; the second determining unit 1112 is configured to determine the next deployment of the domain and the downstream of the domain sequence in which the path computing unit is located. Whether there is a domain in which the PCE is not deployed between the domains of the PCE, the first computing unit 1113 is triggered when not present; and the second computing unit is triggered when it exists;

The first calculating unit 1113 is configured to calculate a virtual shortest path tree VSPT of the domain in which the path calculating unit is located;

The second computing unit 1114 is configured to use an intra-domain abstract link of the domain in which the PCE is not deployed, and an inter-domain link between domains in which the PCE is not deployed as an extended link topology, and the domain in which the path calculation unit is located The link topology is merged to calculate the VSPT of the merged link topology.

On the basis of the path calculation unit shown in FIG. 11, the path calculation unit of this embodiment further includes an identification unit (not shown in FIG. 11) configured to calculate the merged link topology in the second calculation unit 1114. After the VSPT, the VSPT corresponding routing path calculated by the extended link topology and the VSPT corresponding routing path calculated by the domain in which the path calculating unit belongs are identified as different types of routing paths.

On the basis of the path calculation unit shown in FIG. 11, the path calculation unit of this embodiment further includes a third determination unit (not shown in FIG. 11) and a transmission unit (not shown in FIG. 11), wherein:

a third determining unit, configured to: after the VSPT is calculated, determine that the domain where the PCE is located is a non-first domain in the domain where the two or more PCEs are deployed, triggering the sending unit; The calculated VSPT is sent to the PCE of the next PCE-provisioned domain upstream of the domain sequence.

The receiving unit 1110 is further configured to receive a path calculation request message; or, receive the VSPT.

Those skilled in the art should understand that the implementation functions of the processing units in the path calculation unit shown in FIG. 11 can be understood by referring to the related description of the foregoing multi-domain route calculation method. Those skilled in the art should understand that the functions of each processing unit in the path calculation unit shown in FIG. 11 can be transported. It is implemented by a program running on a processor, and can also be implemented by a specific logic circuit.

The invention also describes a routing network comprising more than one routing domain, wherein the routing domain is provided with the path computation unit described above.

Obviously, those skilled in the art should understand that the above various processing units or steps of the present invention can be implemented by a general-purpose computing device, which can be concentrated on a single computing device or distributed among multiple computing devices. Alternatively, the network may be implemented by program code executable by the computing device, such that they may be stored in the storage device by the computing device, or they may be separately fabricated into individual integrated circuit modules, or they may be Multiple modules or steps in the fabrication are implemented as a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software.

The above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention.

Industrial applicability

In the technical solution of the present invention, the domain topology of the domain in which the PCE is not deployed is used as the extension of the inter-domain link in the calculation process of the original BRPC algorithm for the hybrid networking of the domain where the PCE is deployed and the domain where the PCE is not deployed. Park, and use the topology to generate the virtual shortest path tree of the domain in the calculation of the BRPC of each PCE, thereby solving the problem that the BRPC algorithm cannot be implemented due to the existence of the domain without deploying the PCE, and improving the optimality of the path. .

Claims

claims

1. A multi-domain routing calculation method, including:

When it is determined that there are two or more domains in the network where the path calculation unit PCE is deployed, an extended reverse recursive path is used to calculate the BRPC between the first domain PCE and the tail domain PCE in the two or more domains where the PCE is deployed. The routing path is calculated by using RC in domains other than the domains where the two or more PCEs are deployed.

2. The method according to claim 1, wherein the extended BRPC method is used to calculate the routing path between the first domain PCE and the tail domain PCE in the two or more domains where PCE is deployed, including:

After the PCE receives the trigger request for path calculation, it determines whether the domain where the PCE is located is a tail domain. If it is a tail domain, it calculates the virtual shortest path tree VSPT of the local domain. If it is a non-tail domain, it further determines whether the domain where the PCE is located is the same as the tail domain. Whether there is a domain without PCE deployed between the next downstream domain in the domain sequence in which PCE is deployed. If it does not exist, calculate the VSPT of this domain. If it exists, the intra-domain abstract link of the domain without PCE deployed, the intra-domain abstract link of the domain where PCE is not deployed, and the domain where PCE is not deployed. The inter-domain link between domains is used as the extended link topology and merged with the link topology of the domain where the PCE is located, and the VSPT after the merged link topology is calculated.

3. The method according to claim 2, wherein after calculating the VSPT after the merged link topology, the method further includes:

The routing path corresponding to the VSPT calculated through the extended link topology and the routing path corresponding to the VSPT calculated through the domain where the PCE is located are identified as different types of routing paths.

4. The method according to claim 2, wherein the method further includes:

After calculating the VSPT, when it is determined that the domain where the PCE is located is a non-first domain among the two or more domains where the PCE is deployed, the calculated VSPT is sent to the next upstream domain in the domain sequence where the PCE is deployed. PCE.

5. The method according to claim 4, wherein the PCE receives a trigger request for path calculation, including: The PCE receives the path calculation request message;

Or, the PCE receives the VSPT.

6. The method according to claim 3, wherein after the two or more PCEs are deployed, the method further includes:

Send signaling from the source node to the destination node;

When the signaling is routed to the VSPT corresponding routing path calculated through the domain where the PCE is located, the signaling is routed according to the VSPT corresponding routing path;

When the signaling is routed to the routing path corresponding to the VSPT calculated through the extended link topology, the intra-domain strict hop path corresponding to the loose hop path of the domain where PCE is not deployed is further calculated, and the signaling is routed according to the calculated strict hop path. make.

7. A multi-domain route calculation device, including a determination unit and a calculation unit, wherein: the determination unit is configured to determine that the path calculation unit PCE is deployed in the network and trigger the calculation unit when there are two or more domains;

The computing unit is configured to use the extended reverse recursive path calculation BRPC method to calculate the routing path between the first domain PCE and the tail domain PCE in the two or more domains where PCEs are deployed. Domains outside the domain with PCE use RC to calculate routing paths.

8. The device according to claim 7, wherein the calculation unit includes a receiving sub-unit, a first determining sub-unit, a second determining sub-unit, a first calculating sub-unit and a second calculating sub-unit, wherein:

The receiving subunit is configured to receive a trigger request for path calculation;

The first determination subunit is configured to determine whether the domain where the PCE of the computing unit belongs is a tail domain, and trigger the first computing subunit when it is; when it is a non-tail domain, the second determination subunit is triggered;

The second determination subunit is configured to determine the domain and domain sequence of the PCE to which the computing unit belongs. Whether there is a domain in which PCE is not deployed between the next downstream domains in the column in which PCE is deployed. If it does not exist, the first computing subunit is triggered; if it exists, the second computing subunit is triggered;

The first calculation subunit is configured to calculate the virtual shortest path tree VSPT of the domain where the PCE to which the calculation unit belongs is located;

The second computing subunit is configured to use the intra-domain abstract link of the domain where the PCE is not deployed and the inter-domain link between the domains where the PCE is not deployed as the extended link topology, and connect it to the location of the PCE to which the computing unit belongs. The link topologies of the domains are merged, and the VSPT of the merged link topology is calculated.

9. The apparatus according to claim 8, wherein the calculation unit further includes an identification subunit configured to, after the second calculation subunit calculates the VSPT of the merged link topology, the extended link topology. The routing path corresponding to the VSPT calculated by PC and the routing path corresponding to the VSPT calculated through the domain where the PCE to which the computing unit belongs is identified as different types of routing paths.

10. The device according to claim 8, wherein the calculation unit further includes a third determining subunit and a sending subunit, wherein:

The third determination subunit is configured to trigger the sending subunit when, after calculating the VSPT, it is determined that the domain where the PCE is located is a non-first domain among the two or more domains where the PCE is deployed; the sending subunit, The PCE is configured to send the calculated VSPT to the next upstream domain in the domain sequence in which the PCE is deployed.

11. The device according to claim 10, wherein the receiving subunit is further configured to receive a path calculation request message; or, receive a VSPT.

12. The device according to claim 9, wherein the device further includes a sending unit and a routing unit, wherein:

A sending unit configured to send signaling from the source node to the destination node;

The routing unit is configured to route the signaling according to the VSPT corresponding routing path when the signaling is routed to the VSPT corresponding routing path calculated through the domain where the PCE is located; when the signaling is routed to the extended link topology When the VSPT calculated by Piao corresponds to the routing path, RC calculation is further used. Calculate the intra-domain strict hop path corresponding to the loose hop path of the domain where PCE is not deployed, and route the signaling according to the calculated strict hop path.

13. A path calculation unit, including a receiving unit, a first determination unit, a second determination unit, a first calculation unit and a second calculation unit, wherein:

a receiving unit configured to receive a trigger request for path calculation;

The first determination unit is configured to determine whether the domain where the path calculation unit is located is a tail domain, triggering the first calculation unit when it is a tail domain; triggering the second determination unit when it is a non-tail domain; the second determination unit , configured to determine whether there is a domain in which PCE is not deployed between the domain where the path calculation unit is located and the next downstream domain in the domain sequence in which PCE is deployed, and trigger the first calculation unit when it does not exist; trigger the first calculation unit when it does exist; second computing unit;

The first calculation unit is configured to calculate the virtual shortest path tree VSPT of the domain where the path calculation unit is located;

The second calculation unit is configured to use the intra-domain abstract link of the domain where PCE is not deployed and the inter-domain link between domains where PCE is not deployed as an extended link topology, and compare it with the domain where the path calculation unit is located. The link topologies are merged, and the VSPT of the merged link topology is calculated.

14. The path calculation unit according to claim 13, wherein the path calculation unit further includes an identification unit configured to, after the second calculation unit calculates the VSPT of the merged link topology, pass the extended link The routing path corresponding to the VSPT calculated by the topology and the routing path corresponding to the VSPT calculated through the domain where the path calculation unit is located are identified as different types of routing paths.

15. The path calculation unit according to claim 14, wherein the path calculation unit further includes a third determination unit and a sending unit, wherein:

The third determination unit is configured to trigger the sending unit after calculating the VSPT and determining that the domain where the PCE is located is a non-first domain among the two or more domains where the PCE is deployed;

The sending unit is configured to send the calculated VSPT to the PCE of the next upstream domain in the domain sequence in which the PCE is deployed.

16. The path calculation unit according to claim 15, wherein the receiving unit is further configured to receive a path calculation request message; or, receive a VSPT.

17. A routing network including more than one routing domain, the routing domain being provided with the path calculation unit according to any one of claims 13 to 16.